1. Field of the Invention
This invention relates to a vehicle wiper apparatus.
2. Description of the Related Art
A vehicle wiper apparatus is mounted in the vicinity of a windshield glass of a vehicle. A wiper blade of the vehicle wiper apparatus is reciprocated in an arcuate wiping area so that a blade rubber attached to the wiper blade wipes off deposits, such as rainwater or snowflakes, adhering to the surface of the windshield glass. Moreover, the surface of the windshield glass is sprayed with a washer fluid to allow the smooth motion of the blade rubber and improve the wiping of the deposits.
Examples of a spray nozzle for spraying the washer fluid include that fixed to a wiper arm, that fixed to a stay for connecting the wiper blade and the wiper arm (see, for example, Japanese Patent Application Laid-Open No. 2000-177539), and that fixed to an engine hood of a vehicle (see, for example, Japanese Patent Application Laid-Open No. 1998-6933).
The vehicle wiper apparatus having the spray nozzle fixed to the wiper arm, however, faces the following problem: If the spray nozzle is set to spray the washer fluid in the upward wiping direction of the wiper blade, it follows that during downward wiping with the wiper blade, the washer fluid is sprayed rearwardly in the downward wiping direction of the wiper arm. As a result, the washer fluid keeps remaining on the surface of the windshield glass until the wiper arm wipes upward, thereby deteriorating a vehicle driver's field of vision. Furthermore, if the washer fluid is sprayed when the wiper arm is located in proximity to the position of its inversion (i.e., the position of a change in the direction of its movement), the washer fluid is sprayed onto a area where the blade rubber does not wipe. Thus, the problem arises that a surplus of the washer fluid is used.
With the vehicle wiper apparatus described in Japanese Patent Application Laid-Open No. 2000-177539, the washer fluid is sprayed from the spray nozzle, whereby the wiper blade is allowed to move smoothly and easily wipe off deposits on the surface of the windshield glass. However, when the washer fluid is sprayed from the spray nozzle during the downward wiping action of the wiper arm, the washer fluid is sprayed rearwardly in the downward wiping direction of the wiper arm. This washer fluid remains on the surface of the windshield glass until the wiper arm wipes upward, thereby deteriorating the vehicle driver's field of vision. Furthermore, if the washer fluid is sprayed when the wiper arm is located in proximity to the position of its inversion, the washer fluid is sprayed onto the area where the wiper arm does not wipe. This poses the problem that a surplus of the washer fluid is used.
With the vehicle wiper apparatus for the windshield glass described in Japanese Patent Application Laid-Open No. 1998-6933, the position of spraying and the timing of spraying of the washer fluid can be controlled according to the position of the wiper arm. However, the spray nozzle has to be provided on the engine hood, and mechanisms for controlling the spray position and the spray timing for the washer fluid are provided within the washer nozzle, thus posing the problem that the apparatus per se is complicated.
The present invention has been proposed in light of the above-described problems. It is an object of the invention to provide a vehicle wiper apparatus which has a simple structure, and which can spray the washer fluid onto an optimal area regardless of the position of the wiper blade.